1. Technical Field
The present invention relates to a drilling apparatus and a drilling method.
2. Related Art
There has been known a drilling apparatus that forms a hole in a work with a drill rotated at high speed. In drilling performed using such a drilling apparatus, when holding rigidity of the apparatus is insufficient, the apparatus may slightly displaced because of machining reaction from the work during the drilling, thereby deteriorating machining accuracy of the hole. In particular, in a drilling apparatus used as an end effector of a multi-joint robot in which a plurality of arms is coupled, holding rigidity of the apparatus is low compared with a drilling apparatus mounted on a general drilling machine including a smaller number of movable components. Therefore, deterioration in the machining accuracy may easily occur.
Measures are taken to cope with this problem such as increasing the rigidity of a holding structure of the drilling apparatus, adding control for detecting a displacement of the dill due to machining reaction, and adjusting a feed rate of a drill. However, these measures cause an increase in size and complication of control of an entire working machine including the drilling apparatus. Therefore, there is a demand for a technique for making it possible to suppress the deterioration in the machining accuracy with a simpler configuration.
Therefore, for example, a drilling apparatus described in Japanese Unexamined Patent Application Publication No. 2004-9228 employs a pressing body capable of pressing the periphery of a drilling position of a work. The hole is formed with the drill while the work is pressed with the pressing body, thereby suppressing misalignment between the work and the apparatus.
However, simply pressing the work during drilling may cause deformation of the work due to an excessively large pressing force, and the deterioration in the machining accuracy cannot be reliably prevented. In particular, for example, when an erected tabular work is machined, in a state in which a rear surface (a surface on the opposite side of a surface on a drill advancing side) of the work is not supported, deformation of the work on the rear surface side due to pressing from the surface on the drill advancing side may easily occur.